1. Field of the Invention
The present invention relates to a recording and reproducing apparatus, and more particularly to a recording and reproducing apparatus arranged to perform a recording or reproducing action by pulling out a tape-shaped recording medium from a cassette and wrapping the tape-shaped recording medium around a rotary drum.
2. Description of Related Art
Each of conventional recording and reproducing apparatuses, such as a video tape recorder (VTR) and a digital audio tape recorder (DAT), is provided with a tape loading apparatus, which is arranged to, in loading a tape cassette, pull out a magnetic tape from the tape cassette and to wrap the magnetic tape around the peripheral circumferential surface of a rotary drum over a predetermined angular range.
The tape loading apparatus is provided with guide posts for pulling the tape out from the tape cassette when the tape cassette is loaded, guide-post moving members (hereinafter referred to as the guide post bases) on which the guide posts are mounted, and cam grooves which guide the guide post bases along the circumferential surface of the rotary drum.
When the recording and reproducing apparatus is loaded with the tape cassette, the guide posts serving to pull out the tape wrap the tape around the peripheral circumferential surface of the rotary drum while pulling out the tape from the tape cassette in conjunction with the guide post bases, and are then positioned and press-fixed at their loading completion positions, thereby forming a tape travel path including the circumferential surface of the rotary drum.
In the recording and reproducing apparatus of the kind having such a tape loading apparatus, for the purpose of attaining a reduction in size, two chassis, whose relative positions differ at the time of loading of the tape cassette and at the time of recording or reproduction, are used, and the angle of wrapping of the tape around the circumferential surface of the rotary drum is increased by reducing the diameter of the rotary drum.
For example, as disclosed in Japanese Patent Publication No. Hei 7-56742, Japanese Laid-Open Patent Application No. Hei 5-6600, etc., the reduction in size of a recording and reproducing apparatus is attained by cutting out a mouth part of the tape cassette to enlarge a space for accommodating a rotary drum. This method for reduction in size, however, causes an increase in the number of posts to be used, producing a disadvantage in terms of cost, and also lessens the length of recordable time on the tape.
In addition, according to the conventional method for reduction in size, although the size of the rotary drum is decreased to provide additional space, the presence of tape guide members in the space hinders the effective use of the space.
Further, if the guide post bases fail to be correctly positioned with respect to the rotary drum at the tape loading completion positions, the tape wrapping angle and the tape wrapping start and end positions, which determine a signal recording track position on the magnetic tape, cannot be accurately set. Then, in reproducing a signal from the magnetic tape, track deviations arise to make it hardly possible to retain adequate interchangeability and to retain an adequate rate of positional accuracy with repeated tape loading operations. It is, therefore, necessary to provide a positioning mechanism for stably positioning the guide post bases to ensure no rattling.
The guide post bases may be stably positioned without rattling, by using an elastic positioning means. In order to have adequate positioning accuracy, however, the elastic positioning means must have a strong elastic force. To meet this requirement, an elastic member to be used for this purpose must be arranged to have a large number of turns. However, this arrangement using such an elastic member requires a larger space.